화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.103, No.49, 10737-10740, 1999
Photochemical switching of vesicle formation using an azobenzene-modified surfactant
Formation and disruption of vesicles could be photochemically controlled in aqueous mixtures of a "photo-switchable" azobenzene-modified cationic surfactant (4-butylazobenzene-4'-(oxyethyl)trimethylammonium bromide; AZTMA) and an anionic surfactant (sodium dodecylbenzenesulfonate; SDBS). Vesicles were formed spontaneously in a wide composition range in aqueous trans-AZTMA/SDBS mixtures. AZTMA molecules constituting vesicles underwent reversible trans-cis photoisomerization upon alternate UV and visible-light irradiation. Transmission electron microscopic observations via freeze replica technique demonstrated the disruption of the vesicles into larger aggregates (precipitate) with UV-light irradiation (cis formation) and the following visible-light irradiation (trans formation) resulted in vesicle reformation. Furthermore, the release rate of aqueous compounds encapsulated in vesicles was shown to be photochemically controllable in the present AZTMA/SDBS mixed system.